Method of removing, with the use of water, soot and like deposits which adhere more or less fixedly to the walls of boiler flues, and apparatus for practising the method



Oct. 2, 1962 H. OSTERLIN 3,056,700 METIIOD OF REMOVING, WITH THE USE OF WATER, SOOT AND LIKE DEPOSITS WHICH ADHERE MORE OR LESS FIXEDLY TO THE WALLS OF BOILER FLUES, AND APPARATUS FOR PRACTISING THE METHOD Filed Oct. 28. 1959 IIIII United States Patent METHOD OF REMOVTWG, WITH THE USE OF WATER, SOOT AND LIKE DEPOSITS WHECH ADHERE MORE OR LESS FIXEDLY TO THE WALLS OF BOILER FLUES, AND APPARATUS FOR PRACTHSING THE METHQD Hilding Osterlin, Kopenhamnsvagen 11 A., Maimo v., Sweden Fiierl Oct. 28, 1959, Ser. No. 849,242 Claims. (Cl. 134-17) This invention relates to a method of removing, with the use of water, soot and like deposits which adhere more or less fixedly to the Walls of boiler flues, and to an apparatus for practising the method.

It is well known that soot, boiler scale etc. will deposit more or less rapidly on the walls of flues or other surfaces swept by the combustion gases in central-heating boilers, water heaters and the like. To remove such deposits which adhere more or less fixedly to the flue walls thereof is a dirty and time-consuming work. It is also very difiicult to remove the deposit adhereing to the walls of the boiler flues, and in certain cases it must even be chipped off with the aid of chiscls. For this reason soot and like deposits are often permitted to remain on the flue walls, in which case one has to resign oneself to a considerably decreased performance of the boiler. In most cases the boiler is cleaned only at the officially prescribed occasions but such cleaning and resulting removal of the deposit on the flue walls leaves much to be desired.

According to the invention, water in finely dispersed form is supplied to the smoke gas flues of the inoperative but hot boiler to such an extent and in such a way that the water particles are absorbed as much as possible by the deposit on the flue walls and will not or but insignificantly collect again and flow down in streams along the deposit while taking along loose particles of the deposit. The boiler is now put in operation again and/ or its performance increased so that so high and sudden a temperature increase is brought about that there will be produced in the water absorbed by the deposit a strong generation of steam which bursts and tears loose the deposit from the flue walls.

The finely dispersed water can either have room temperature or be given an elevated temperature by heating. It is less risky to use heated Water, as a hot boiler will not then be exposed to any injurious heat changes. The supply of water must not be so large that the Water collects again and flows down along the boiler Walls. How ever, it is of course impossible in practice to regulate the supply of the finely dispersed water so precisely that the water will not to some extent collect again and flow down along the surfaces to be cleaned, thereby taking along loose particles. Furthermore, the supply must not be so ample that when solid fuels are used the fire in the boiler is extinguished or the performance of the boiler is reduced so considerably as to jeopardize the shock action generated by the suddenly increased furnace performance and the resulting evaporation of the water absorbed by the deposit. The heat of the boiler walls leads to a more rapid generation of steam inasmuch as the flue walls take up and lead away the generated heat but to a limited extent, and the generation of steam thus takes place explosively and bursts the solid deposit by shock action, tearing it loose from the walls. The boiler walls must not, however, be so hot that a considerable steam generation takes place already before the performance of the heat source is increased.

In the event that the deposit adhering to the flue walls is so strong that it does not burst and is not torn loose at the first treatment, it is possible to repeat the treatment one or more times until the deposit has been completely removed.

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To increase the capability of the water to be absorbed by the deposit or otherwise to increase the contemplated eflect of the treatment the water may be admixed with any suitable additive.

The deposit is caused to a high extent by sulphur and sulphur compounds. To obviate that the sulphur in the deposit reacts with the water supplied and forms sulphur trioxide which will damage the boiler, the water may be admixed with soda, which may be effected in any suitable manner.

A suitable apparatus for practising the method according to the invention is illustrated in the accompanying drawing in which:

FIG. 1 is a side elevational view of the apparatus;

FIG. 2 is a section of the atomizer of the apparatus, and

FIG. 3 is a View showing the apparatus in use.

The apparatus comprises an atomizer .1 in the form of a nozzle arranged at the end of a water supply pipe 2, and a cock 3 for opening and closing the communication between the pipe 2 and a suitable water supply. The cock 3 is preferably built into a gun-like support 4 which has a connecting socket 5 for a hose 6 which is connected to a hot water main (not shown). The atomizer 1 consists of a body 7 having obliquely bored atomizer ducts 8, a nozzle disk 9 with performations 10 and a ring nut 11 which holds the nozzle disk 9 in position in front of the atomizer body '7 and a space 12 provided between said body and the ring nut 11.

When the described atomizer is moved along the walls 1'3 of the boiler flue 14 (shown partly in FIG. 3) the deposit 15 on the flue wall absorbs the spray 16 of extremely finely dispersed water discharged through the nozzle. The deposit 15 is then exposed to a heat shock as earlier mentioned, whereby it will burst and be torn loose from the flue wall 13.

From a container (not shown) mounted on the support 4 and connected by said support to a duct (likewise not shown), soda or other lump additive is admixed with the water flowing in said duct.

What I claim and desire to secure by Letters Patent is:

1. A method of removing a deposit adhering to the Wall of a boiler flue comprising depositing a liquid in mist form on the flue of a hot inoperative boiler and suddenly elevating the temperature within said boiler to cause said mist to evaporate and tear loose the deposit from the flue wall. Z

2. A method as claimed in claim 1 wherein said liquid is water.

3. A method as claimed in claim 1 wherein said liquid is a mixture of water and soda.

4-. A method of removing a deposit adhering to the wall of a boiler flue comprising spraying Water on the flue of a hot inoperative boiler thereby causing water particles to be absorbed by said deposit and operating said boiler to increase the temperature suddenly whereby said water is converted to steam which tears loose the deposit from the flue wall.

5. A method as claimed in claim 4 comprising heating the water before spraying it on the flue.

References Cited in the file of this patent UNITED STATES PATENTS 1,460,094 Cunnecn June 26, 1923 2,425,134 Strickland Aug. 5, 1947 2,591,364 Kurth Apr. 1, 1952 2,628,204 Gray Feb. 10, 1953 2,671,741 Duvall Mar. 9, 1954 2,762,729 Snow Sept. 11, 1956 2,908,445 Schwartz Oct. 13, 1959 

1. A METHOD OF REMOVING A DEPOSIT ADHERING TO THE WALL OF A BOILER FLUE COMPRISING DEPOSITING A LIQUID IN MIST FORM ON THE FLUE OF A HOT INOPERTIVE BOILER AND SUDDENLY ELEVATING THE TEMPERATURE WITHIN SAID BOILER TO CAUSE SAID MIST TO EVAPORATE AND TEAR LOOSE THE DEPOSIT FROM THE FLUE WALL. 